发明名称 Combination screw-tapping and screwdriving tool
摘要 A drill accessory kit for mounting screw-type fasteners is comprised of several drill bit holders and a screwdriving attachment. The bit holder engages a common twist drill bit in the chuck of a drill and allows one to drill a pilot hole to a desired depth in a workpiece with a cutting action which provides a proper-shaped hole for clean flush mounting or countersinking of a screw. Subsequently, the screwdriver attachment slips over the drill bit and engages with the bit holder, allowing a quick change from drilling to powerdriving of a screw.
申请公布号 US4796319(A) 申请公布日期 1989.01.10
申请号 US19870060654 申请日期 1987.06.11
申请人 TAFT, DAVID 发明人 TAFT, DAVID
分类号 B25B21/00;B25F3/00;(IPC1-7):B25F3/00 主分类号 B25B21/00
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